What is Next for BCG Revaccination to Prevent Tuberculosis?

Early this year, the confirmatory phase 2b trial results on whether Bacillus Calmette–Guérin (BCG) revaccination prevents tuberculosis infection, or more accurately, whether it prevents conversion to a positive interferon-γ release assay (IGRA) test sustained over 6 months, will become available (NCT04152161). Unfortunately, despite rigorous analysis,1 the ability of BCG revaccination to prevent tuberculosis infection is not a reliable indicator of whether it would prevent tuberculosis disease.